Question

A person clapped his hands near a cliff and heard the echo after $4\text{s}$. What is the distance of the cliff from the person if the speed of the sound is taken as $340\text{m/s}$?

• A. $340\text{m}$
• B. $680\text{m}$
• C. $460\text{m}$
• D. $170\text{m}$

Answer 1

The correct option is B $680\text{m}$

Let the distance of the cliff from the person is $d$.

Then,

$v=\frac{2d}{t}$

$\Rightarrow d=\frac{vt}{2}=\frac{340\times 4}{2}=680\text{m}$

​​​​​​​Hence, option $\left(B\right)$ is the correct answer.